I think the difference is when people deliberately violate a rule they at least should have known vs. just showing that they are an outsider by not seeming to k

I think the difference is when people deliberately violate a rule they at least should have known vs. just showing that they are an outsider by not seeming to know it. Of course, there are all kinds of variations and cases in between. Fashion is, among other things, a communication code and a signal of conformism or dissent. Besides, the rules about wearing a hat inside can be quite complex: women have to wear a had while men have to take it off (traditional church service in Europe); high ranking men wearing their hats, while lower ranking men have to take them off; petitioners removing their hat in front of the benefactor ...